JSON vs YAML
JSON vs YAML compared — syntax, readability, comments, data types and speed, plus when to use each and free tools to convert between them.
JSON and YAML both describe structured data, and YAML is actually a superset of JSON — every JSON document is valid YAML. The difference is ergonomics: JSON uses explicit braces and brackets and is ubiquitous in APIs, while YAML uses indentation and is favoured for human-edited config files.
JSON vs YAML at a glance
| JSON | YAML | |
|---|---|---|
| Syntax | Braces {} and brackets [], quoted keys | Indentation, minimal punctuation |
| Comments | Not supported | Supported with # |
| Readability | Compact, machine-friendly | Human-friendly for config |
| Data types | Strings, numbers, bool, null, array, object | Same + anchors, references, multi-line strings |
| Parsing | Fast, everywhere | Slower, indentation-sensitive |
| Typical use | APIs, web payloads | CI/CD, Kubernetes, app config |
When to use JSON
Choose JSON for API responses and data interchange — it is faster to parse, supported everywhere, and unambiguous. If a machine reads it, JSON is usually the safer default.
When to use YAML
Choose YAML for files humans edit by hand — CI pipelines, Docker Compose, Kubernetes manifests — where comments and clean indentation matter more than parse speed.
Tools for JSON & YAML
JSON vs YAML
日期和布尔值是如何转换的？
js-yaml 遵循 YAML 1.2 规范 —— 日期会被转换为 ISO 格式字符串，true/false 会被转换为布尔值。而 "yes"/"no" 则按 1.2 规范保留为字符串。
包含多个文档（以 --- 分隔）的 YAML 该怎么处理？
转换只会处理第一个文档。如需处理多个文档，请先按 `---` 将字符串拆分开。
这个工具能处理 YAML 中的 anchor 和 alias 吗？
可以 —— anchor（&）和 alias（*）会在解析阶段被解析（resolve），并在生成的 JSON 中产生对应的重复数据。